Spreader for spreading a fluid, such as an adhesive

ABSTRACT

A spreader for spreading a fluid, such as an adhesive, in a thin layer on a surface including a spreader housing and a plurality of outlet nozzles, which are arranged at regular intervals along one side of the spreader housing, and which are connected to a feeding channel system accommodated in the housing. The feeding channel system communicates with an inlet opening for the fluid. The nozzles, the feeding channel system thereof and the inlet opening are shaped in a separate lining detachably secured in the housing, the housing including cavities for receiving the lining and being able to firmly clamp around the lining in use, and whereby at least one opening is provided in the housing, where the nozzles project from the interior of the housing through the opening.

TECHNICAL FIELD

The invention relates to a spreader for spreading a fluid, such as anadhesive, in a thin layer on a surface, said spreader comprising anoblong spreader housing and a plurality of outlet nozzles which arearranged at regular intervals along one side of the spreader housing,and which are connected to a feeding channel system accommodated in thehousing and in turn connected to an inlet opening for said fluid.

BACKGROUND ART

It is known to apply adhesive onto a large surface through a number ofnozzles in a spray spreader. The adhesive in question is pumped from asuitable source to a coupling device through a conduit, said conduit orconduits (used in connection with a two-component adhesive) beingconnected to the spreader. The known spreader comprises often a pipe orbar-like member of a length rendering it possible to coat the surface inquestion with the adhesive layer in question by way of a single relativemovement of said surface past the spreader. Therefore, the nozzles inquestion are arranged adjacent one another at regular intervals. Suchspreaders are for instance used in connection with plants, where theplates to be coated with an adhesive layer are advanced stepwise on aconveyor belt, said plates being advanced in lengths corresponding tothe length of a spreader, such as 0.5 m, in each step. Subsequently, thespreader is moved transverse to the advancing path of the conveyor beltat the same time as adhesive is fed through the nozzles of the spreader.After each transverse movement of the spreader, the plate placed on theconveyor belt is advanced yet another step. Such plants can for instanceprocess plates of up to 3 times 6 m to be used for the production ofsandwich elements. The adhesive types in question are typicallyhigh-viscous fluids requiring a high pressure, such as 20 to 180 bar, inorder to be pressed through feeding conduits and nozzles. A spreader forapplying adhesive onto such plates comprises a very high number ofnozzles, and accordingly it is very difficult to keep such nozzles cleanor to clean said nozzles after the use thereof. Often it is not possibleto carry out such a cleaning process without the use of suitablesolvents. Accordingly, the cleaning process is both cost-intensive andtime-consuming.

BRIEF DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a spreader avoidingthe necessity of a cost-intensive and time-consuming cleaning process aswell as the use of separate solvents.

The above is obtained by the spreader according to the invention beingcharacterised in that the nozzles, their feeding channel system, and theinlet opening being shaped in a separate lining detachably secured inthe housing, whereby the housing comprises cavities receiving the liningand being adapted to fixedly clamp around said lining during the use ofthe spreader, at least one opening being provided in said housing, wherethe nozzles project from the interior of the housing through saidopening.

When this spreader is used, nothing but the lining is replaced by a newlining when required by the nozzles or the associated feeding channelsystem.

The lining may particularly advantageously comprise two interconnected,substantially plate-shaped lining members with recesses provided thereinto form the nozzles the feeding channel system of said nozzles as wellas the inlet opening. Such plate-shaped lining members are easy tomanufacture of a suitable disposable material, such as board orplastics.

The housing may according to the invention comprise two hingedlyinterconnected housing parts provided with means for tightening saidhousing parts around the lining with the result that the opening and theclosing of said housing is particularly simple.

Moreover, the lining members may according to the invention be plate orsheet-extruded, vacuum-moulded plates of plastics, which are glued orwelded to one another, whereby the outlet nozzles shaped in one liningmember comprise outlet orifices or openings resulting from a cutting offof portions of said lining member. The resulting manufacture of thelining members is particularly easy and inexpensive.

Furthermore, the nozzles may according to the invention be shaped in anumber of rows protruding from a plane of a first plate-shaped liningmember in such a manner that each nozzle extends from a plane portioncoinciding with the side facing the second lining member, and thefeeding channel system may form a nozzle feeding chamber adjacent saidnozzles, where said nozzle feeding chamber is formed by a coherentrecess in the second lining member opposite said nozzles. As a result, aparticularly simple feeding of the nozzles is obtained.

According to the invention the nozzle feeding chamber may particularlyadvantageously be formed by a small, trough-shaped recess in the secondlining member, where said small trough-shaped recess extends along therow or rows of nozzles and comprises longitudinal sides, of which onelongitudinal side is positioned opposite the area along one side of therow or rows of nozzles and the other longitudinal side is positionedopposite the area along the opposite side of the row or rows of nozzles,but at a predetermined distance therefrom, said latter area beingpositioned upstream relative to the flow direction of the fluid insidethe feeding channel system, and where a comparatively larger recess isprovided opposite the small trough-shaped recess at the upstream sideand along the row or rows of nozzles in the first lining membercomprising said nozzles, whereby a distribution chamber is formed inthis portion of the feeding channel system, said distribution chambercommunicating directly with the nozzle feeding chamber. The spreader isparticularly suited for use in connection with an application processinvolving returning interruptions between the individual applications ofadhesive while producing a multilayer sandwich element or when saidelement is to be replaced. These interruptions can last from 1 minuteand up to several hours. The structure in question of the nozzles withthe associated feeding chamber and distribution chamber ensures that theinterruption does not involve a noticeable afterflow of the adhesive inquestion, which is due to the fact that the adhesive present at a levelabove the nozzles is not significant and that said adhesive is insteadpresent in the distribution chamber at a level below the inlet of eachnozzle. The possible interruption period in question depends, of course,on the type of adhesive in question because said type of adhesive mustnot, of course, be able to cure inside the interior of the nozzlesduring said interruption period.

According to the invention, the portion of the feeding channel systemadjacent the distribution chamber may be formed substantially by one ormore recesses in the first lining member housing the nozzles, wherebythe afterflow of adhesive material in connection with an interruption ofthe application process is not additionally stimulated.

The feeding channel system may according to the invention be providedwith one or more static mixers, whereby the components of the adhesivematerial are efficiently mixed during the flow towards the nozzles. Thisor these static mixer(s) may according to the invention be arranged intheir respective separate tubes, whereby it is ensured that the adhesivematerial does not flow round said static mixers because the separatetubes associated with said mixers can be formed very accurately to fitsaid static mixers.

A static mixer with the associated separate tube may according to theinvention be arranged in connection with the inlet opening and compriseprojecting members with means for coupling the spreader to a mixer head,which in turn comprises means for connecting conduits thereto, saidconduits communicating with sources with their respective components ofa two-component adhesive system. As a result, a particularly simpleconnection is obtained between the lining and the conduit systemadvancing the adhesive to the spreader.

The second lining member may according to the invention be made of aresilient plastic material, and the spreader may comprise means forallowing a closing of each nozzle by pressing the second lining membertowards the first lining member opposite each nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail below with reference to theaccompanying drawings, in which

FIG. 1 is a perspective view of a spreader according to the inventionand connected to a mixer head and conduits associated therewith for thefeeding of the individual components of a two-component adhesive system,

FIG. 2 is a cross sectional, slightly staggered view taken along theline II—II of FIG. 3 of the housing of the spreader of FIG. 1,

FIG. 3 is a view taken along the line III—III of FIG. 2 of one housingpart,

FIG. 4 is a sectional view taken along the line IV—IV of FIG. 5 throughlining members to be arranged inside the spreader housing,

FIG. 5 is a view taken along the line V—V of FIG. 4 through one firstlining member with a static mixer inserted therein,

FIG. 6 is a sectional view taken along the line VI—VI of FIG. 7 througha second embodiment of a spreader according to the invention withassociated lining members and static mixers, the individual parts beingspaced apart for the sake of clarity,

FIG. 7 is a view taken along the line VII—VII of FIG. 6 of one firstlining member associated with the spreader of FIG. 6, said first liningmember being shown with the associated static mixers, and

FIG. 8 is a diametrically sectional view through a closable nozzle of aportion of a third embodiment of a spreader according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The spreader illustrated in FIG. 1 is designated the general referencenumeral 1 and comprises two substantially plate-shaped housing parts 2and 3 hingedly interconnected by means of hinges 4 to 8. These housingparts can be firmly fixed to one another by means of clamping means 9 to18. When firmly fixed to one another, these housing parts 2, 3 form ahousing, through which a fluid, such as an adhesive, can be applied ontoa plate being carried past the spreader 1 at a level therebelow whilesaid spreader 1 is maintained in a state in which the bottom side of thelower housing part 2 is arranged at a substantially horizontal plane.

A conduit 19 connects the spreader 1 with a mixer head 20 by means of acoupling nut 21. The mixer head 20 is connected to two conduits 22 and23 for the feeding of their respective components of a two-componentadhesive system. The two components of the adhesive system are fed tothe conduits 22 and 23 by means of suitable pumps from their respectivesources and mixed in the mixer head 20. The two components of theadhesive system leave the mixer head 20 in a mixed state and flowthrough the conduit 19 into the spreader 1.

As illustrated in FIGS. 2 and 3, the housing parts 2 and 3 of thespreader are provided with recesses or cavities on the opposing sides,said recesses being adapted to receive their respective lining members,cf. FIGS. 4 and 5. These lining members comprise a first lining member32 to be received in the lower housing part 3 and a second lining member33 to be received in the upper housing part 3. Each lining member 32 and33 is made of plate or sheet-extruded plates of plastics. The plate orsheet-extruded plates are vacuum-moulded in such a manner that theydefine a feeding channel system at the reference numeral 34, cf. FIG. 5,when they abut one another. This feeding channel system extends from anopening provided at the reference numeral 35 and to a double row ofnozzles 36 shaped in the first lining member 32. Each row of nozzles 36comprises an outlet opening 37 resulting from a cutting off of plasticmaterial from the vacuum-moulded plate.

The two lining members 32 and 33 are glued or welded to one another andthen placed between the two housing parts 2 and 3. Subsequently, thehousing parts 2 and 3 are tightened together in such a manner that theplane portions of the lining members adjacent the recesses sealinglyabut one another, said recesses defining the feeding channel system 34and the rows of nozzles 36. A comparison of FIGS. 4 and 5 demonstratesthat the recesses in the two lining members are shaped substantiallysymmetrically everywhere from the inlet openings 35 to a distributionchamber 38 arranged parallel to the nozzles 36. The distribution chamber38 is defined by a relatively deep recess 39 in the first lining member32 and a relatively shallow recess 40 continuing into a furtherrelatively shallow recess 41 in the second lining member 33. Therelatively shallow recess extends like a trough opposite the row ofnozzles 36, and the adhesive material flowing through the feedingchannel system 34 and through the distribution chamber 38 is distributedthrough said trough 41 to the nozzles in such a manner that the adhesiveis uniformly distributed to the individual nozzles.

The individual nozzles can be shaped with a varying outlet cross sectionand/or opposite a relatively shallow trough-shaped recess 41 of avarying depth in order to ensure a uniform volume flow rate out of thenozzles 36.

As the feeding channel system 34 continues into a distribution chamberadjacent the nozzles 36, and as most of said distribution chamber in useis positioned in the first lining member at a level below the inlet ofeach nozzle 36, and the trough-shaped nozzle feeding chamber 41 is of arelatively low depth in the second lining member, this structure of thefeeding channel system has the effect that only a relatively smallamount of adhesive is present at a level above said inlet to the nozzleswith the result that an interruption of the propulsion of said adhesivedoes not cause a noticeable afterflow of adhesive out of the nozzles 36.

A tube 45 of plastics or metal is clamped between the lining members 32and 33 in the first portion of the feeding channel system 34, said tubecomprising a static mixer 36 of a conventionally known type, such asKenics sold by Tah Europe Incorporation UK. The tube 45 is shaped suchthat at its end positioned outside the inlet opening 35 it can carry aunion nut 21, cf. also FIG. 1, which is adapted to couple the spreaderto the mixer head 20.

As mentioned above, the housing parts 2 and 3 are provided with recessesallowing the receiving of the lining members 32 and 33. As illustratedin FIGS. 2 and 3, these recesses comprise two rows of through openings47 with chamfered edges 48. These openings 47 are adapted to receivetheir respective nozzles 36 in the first lining member 32 in such amanner that each nozzle is supported by the housing part 2 along itsperiphery.

The embodiment illustrated in FIGS. 6 and 7 of the spreader comprises alower and an upper housing part 52 and 53, respectively, with anassociated first and second lining member 62 and 63. The lining members62 and 63 are shaped slightly different from the previously describedlining members 32 and 33, and accordingly the recesses of the housingparts 52 and 53 are also shaped slightly different so as to fit saidlining members. As illustrated at the reference numeral 64, the feedingchannel system extends from an inlet opening 65 shaped by means of abranch not shown n greater detail. This branch extends through one ofthe housing parts 52 or 53 and comprises a device (not shown in greaterdetail either), which ensures a possibility of coupling said branch to amixer head or the like feeding device. The feeding channel systemextends in a manner defined by symmetrical recesses in the two liningmembers 62 and 63 from the inlet opening to a distribution chamber 66which in turn extends parallel to a row of nozzles 67. The feedingchannel system 64 forms a branching immediately before the distributionchamber 66 in such a manner that said distribution chamber 66 issupplied with adhesive through two channel sections 68 and 69. Arelatively shallow trough-shaped recess 70 is formed in the secondlining member 63 opposite the recess provided in the first lining member62 and defining a portion of the distribution chamber 66. The relativelyshallow trough-shaped recess 70 extends across the nozzles 67 with theresult that it forms a connection between the distribution chamber 66and the inlet opening of the nozzles 67 and accordingly form a chamberfor the feeding of adhesive to the nozzles.

As illustrated in FIG. 6, the lower housing part 52 is provided with alongitudinal slot 71. All the nozzles 67 project from the interior ofthe housing of the spreader 1 through this slot 71 when the two housingparts 52, 53 are tightened together around the lining members 62 and 63.As illustrated in FIGS. 6 and 7, the feeding channel system 64 of thelining members 62 and 63 is shaped in such a manner that said liningmembers can receive static mixers 72, 73 and 74 which are received intheir respective tubes. In the assembled state of the spreader 1 thesestatic mixers are sealingly clamped between the lining members 62 and 63in such a manner that adhesive cannot pass the static mixers round thesetubes. Unlike the lining members, it is very easy to manufacture thesetubes so as to exactly fit the static mixers in such a manner that theadhesive does not pass between the outer periphery of the static mixersand the inner side of said tubes. When the lining members 62, 63 areshaped and tightened between the housing parts 52 and 53 in such amanner that the static mixers can be received in the feeding channelsystem without the use of the separate tubes and such that the flow ofadhesive does not pass round said static mixers, said separate tubescan, of course, be omitted.

Displaceable adjustment means can be provided in connection with eachnozzle, whereby it is possible to adjust the application width of thespreader 1, cf. FIG. 8. These adjustment means 80 are displaceablymounted in the upper housing part 3, such as by means of a threadconnection. Generally speaking, such an adjustment means comprises ashank 81 with a head 82 abutting the second lining member 33, said head82 comprising a convex surface 83 abutting said second lining member 33.Correspondingly, the second lining member is shaped with an annularconvex surface 84 and a dome 85 extending centrally downwards towardseach nozzle 36 so as to sealingly abut the inner side of said nozzle 36at the inlet thereof.

An activation of the adjustment means 80 causes said means to be moveddownwards towards the nozzle 36. Correspondingly, the upper secondlining member 33 must be made of a resilient material implying that suchan activation is possible.

The spreader according to the invention is as mentioned mainly used forapplying a layer of adhesive onto continuously advanced plates, such asmetal plates for the manufacture of sandwich elements. Before the use,the lining is positioned between the housing parts 2 and 3 followed by atightening of said housing parts by means of the clamping means 9 to 18.Then, the adhesive system in question is carried in a conventionallyknown manner to the spreader, optionally in form of two componentsthrough their respective conduits 2, 3 and to a mixer head 20. In themixer head 20, the components are mixed and enter the spreader in whichthe mixing is enhanced by means of the static mixers, such as 46 or 72to 74, arranged therein. The adhesive is carried through the feedingchannel system 34, 64 to and through the nozzles 36, 67 and over therelevant surface to be coated with a coating of adhesive. The describedparticular shaping of the feeding channel system adjacent the nozzles36, 67 with the maximum volume at a level below the inlet opening ofsaid nozzles has the effect that the adhesive applying process isinterrupted for a short or a long period of time depending on the typeof adhesive in question, and without involving a noticeable afterflow ofadhesive through the nozzles and consequently without causing ahardening of said adhesive inside the nozzles. If adhesive neverthelessappears in the nozzles after use for a long time or after aninterruption for a long time, it is not necessary to involve a difficultand time-consuming cleaning process because nothing but the lining ofthe spreader need to be replaced, said lining being relativelyinexpensive to manufacture and consequently suited for disposable use.As mentioned, the application width can be adjusted by means of theadjustment means 80, such as by an activation thereof by means of ascrewdriver. These adjustment means can, however, also be adapted to beadjusted by means of compressed air (not shown).

The lining is made of a suitable plastic or board material. It can forinstance be manufactured by way of vacuum moulding of plate orsheet-extruded plates of a thermoplastic ester, such as PET.

The nozzles can be arranged in one or more rows, and according to anadvantageous embodiment the nozzle opening is of a diameter of 1 to 3mm, and especially 2 mm. The centre distance between the nozzles in thesame row is advantageously 5 to 10 mm in order to ensure a uniform,carpet-like coating. As mentioned, the nozzle diameter can vary acrossthe rows of the spreader in order to ensure the same volume flow rate.

The invention has been described with reference to a preferredembodiment. Many modifications can be carried out without therebydeviating from the scope of the invention. In connection withparticularly large spreaders, it can for instance be a possibility toprovide additional clamping means in addition to the clamping means 9 to18 accommodated along the sides of the spreader, said additionalclamping means being positioned between said sides. For such situations,the linings can be provided with suitable openings 90, cf. FIG. 7, forthe passage of the additional clamping means. The lining has beendescribed as made of two members glued or welded together. The liningcan, however, also be integrally cast by means of suitable solublecores. The two lining members can, if desired, also be joined in thespreader housing in another way beyond gluing or welding.

What is claimed is:
 1. A spreader (1) for spreading a fluid, such as anadhesive, in a thin layer on a surface, said spreader comprising anoblong spreader housing (2, 3; 52, 53) and a plurality of outlet nozzles(36, 67) which are arranged at regular intervals along one side of thespreader housing (2, 3; 52, 53), and which are connected to a feedingchannel system (34, 64) accommodated in the housing and in turnconnected to an inlet opening (35, 65) for said fluid, characterised inthat the nozzles (36, 67), their feeding channel system (34, 64) and theinlet opening (35, 65) are shaped in a separate lining (32, 33; 62, 63),detachably secured in the housing (2, 3; 52,53), whereby the housing (2,3; 52, 53) comprises cavities receiving the lining (32, 33; 62, 63) andbeing adapted to fixedly clamp around said lining (32, 33; 62, 63)during the use of the spreader, at least one opening (47, 71) beingprovided in said housing (2, 3; 52, 53), where the nozzles (36, 65)project from the interior of the housing (2, 3; 52, 53) through saidopening.
 2. A spreader as claimed in claim 1, characterised in that thelining comprises two interconnected, substantially plate-shaped liningmembers (32, 33; 62, 63) with recesses provided therein to form thenozzles (36, 67), the feeding channel system (34, 64) of said nozzles aswell as the inlet opening (35, 65).
 3. A spreader as claimed in claim 1,characterised in that the housing comprises two hingedly interconnectedhousing parts (2, 3) provided with means (9 to 18) for tightening saidhousing parts (2, 3) around the lining.
 4. A spreader as claimed inclaim 2, characterised in that the lining members (32, 33; 62, 63) areplate or sheet-extruded, vacuum-moulded plates of plastics which areglued or welded to one another, whereby the outlet nozzles (36, 67)shaped in one lining member comprise outlet orifices or openings (37)resulting from a cutting off of portions of said lining member.
 5. Aspreader as claimed in claim 2, characterised in that the nozzles (36,67) are shaped in a number of rows protruding from a plane of a firstplate-shaped lining member (32, 62) in such a manner that each nozzle(36, 67) extends from a plane portion coinciding with the side facingthe second lining member (33, 63), and that the feeding channel system(34, 64) forms a nozzle feeding chamber (41, 70) adjacent said nozzles(36, 67), where said nozzle feeding chamber is formed by a coherentrecess in the second lining member (33, 63) opposite said nozzles (36,67).
 6. A spreader as claimed in claim 5, characterised in that thenozzle feeding chamber (41, 70) is formed by a small trough-shapedrecess in the second lining member, where said small trough-shapedrecess extends along the row or rows of nozzles (36, 67) and compriseslongitudinal sides, of which one longitudinal side is positionedopposite the area along one side of the row or rows of nozzles (36, 67)and the other longitudinal side is positioned opposite the area alongthe opposite side of the row or rows of nozzles, but at a predetermineddistance therefrom, said latter area being positioned upstream relativeto the flow direction of the fluid inside the feeding channel system(34, 64), and where a comparatively larger recess is provided oppositethe small trough-shaped recess at the upstream side and along the row orrows of nozzles (36, 67) in the first lining member (32, 62) comprisingsaid nozzles (36, 67), whereby a distribution chamber (38, 66) is formedin this portion of the feeding channel system (34, 64), saiddistribution chamber communicating directly with the nozzle feedingchamber (41, 70).
 7. A spreader as claimed in claim 6, characterised inthat the portion of the feeding channel system (34, 64) adjacent thedistribution chamber (38, 66) is formed substantially by one or morerecesses in the first lining member (32, 62) housing the nozzles (36,67).
 8. A spreader as claimed in claim 1, characterised in that one ormore static mixers (46; 72, 73, 74) is/are provided in the feedingchannel system (34, 64).
 9. A spreader as claimed in claim 8,characterised in that the static mixer(s) (46; 72, 73, 74) is/arearranged in their respective tubes.
 10. A spreader as claimed in claim8, characterised in that a static mixer (46) with the associatedseparate tube is arranged in connection with the inlet opening (35) andcomprises projecting members with means for coupling the spreader (1) toa mixer head (20), which in turn comprises means for connecting conduits(22, 23) thereto, said conduits communicating with sources with theirrespective components of a two-component adhesive system.
 11. A spreaderas claimed in claim 4, characterised in that the second lining member(33, 63) is made of a resilient plastic material, and that the spreader(1) comprises means (80) for allowing a closing of each nozzle (36, 67)by pressing the second lining member (33, 63) towards the first liningmember (32, 62) opposite each nozzle (36, 67).
 12. A spreader as claimedin claim 2, characterised in that the lining members (33, 63) areintegrally cast.